Pressure-gage.



Patented Sept. 23, 1913.

E. E e. BUTEEEss.'

'PRESSURE GAGE.

APPLICATION FILED AUG. 25, 1009.

continuous chamber extending @ATE PAEN UFFCE.

HUWAB) BTTRESS AND GEORGE BUTTBESS, OF'LOS ANGELES, CALIFORNIA..

TRESSURE-GAGE.

Specication of Letters Patent.

Patented Sept. 23, 1913.

Application led August 25, 1909. Serial No. 514,630.

To all whom it may concern:

Be it known that we, Hov'vsuo BUT'rREss and Gronau Bowness, bothcitizens of the United States, residing at Los Angeles, in the county ofLos Angeles and State ot California, have invented new and usefulImprovements in Pressure-Gages, of which the following is aspecification.

This invention relates to a pressure gage designed particularly fordetermining the pressure of air in an automobile tire, and one of themain objects of the invention 1s to produce a pressure gage of thischaracter which is of extremely simple construction, compact, light inweight, and which may readily be applied to the valve of the tire todetermine the pressure.

A further im ortant object of the invention is to provi e for securing aperfect airtight connection with the rim ot' the valve, so that air isprevented from escaplng and the full pressure from the tire is caused topass into the gage, and to secure this perfect airtight union by aparticular' construction of the contacting portion of the gage, whichwill produce this close and airtight union by simply pressing the gageagainst theend of the valve.

A further object is to construct the gage of telescopic tubular members,

nearly the entire length of the gage which will receive a spring ofmaximum length which is desii-able for producing accurate registrationof pressure, short springs being less accurate;

Referring to the ldrawingsz--Figure 1 1s an enlarged, longitudinal,cross section through-the gage, showing the manner of applying the gageto the valve. Fig. 2 is a side elevation with the outer tube insection.` Fig. 3 is a section on line 00L-w3 Fig. 2.

rlhe pressure gage comprises an outer tube 1 with a closed head 2, theouter tube 1 closely fitting and telescoping with an inner tube 3. Theouter and inner tubes 1 and 8 constitute a closed air chamber which isextensible in length by 'sliding the outer tube 1 upwardly, and in orderto render such chamber airtight a cupped leather 4 is provided at theend of the inner tube 3 to seal the joint between the inner tube 3 andthe outer tube 1, the cu ped leather 4 being held against the end o theinner tube 3 by a shouldered plug 5 which is screwed into the providinga g end of the inner tube 3. Pressure within the chamber formed by thetwo tubes 1 and 3 acts to press the sides of the cupped leather etoutwardly into close contact with the outer tube 1 and thus preventleakage.

The outer tube 1 is normally held retracted by coiled tensionspring 6,the upper end of which is secured to a pin 7 which extends diametricallythrough the upper part of the outer tube 1, while the lower end of thespring is secured to a pin 8 which extends through the lower lend of thetube 3. The plug 5, projects slightly above the cupped leather s andacts as a stop for the pin 7 to strike against without touching the edgeot the cupped leather t when the outer tube 1 is retracted by thespring. 'Ihe hole through the plug 5 is slightly larger than the springG and acts to hold the upper end of the spring G in central osition. Thelower portion of the inner tube 3 is formed with a circumferentialconcave shallow groove 9 knurled externally to form a finger grip.Screwed in the lower end of the inner tube 3 is a plug 10 which has aflange 11 which strikes against the end of the tube 3 and is also formedwith a central projecting stud 12. An air passage 13 extendslongitudinally of the plug 10 and stud 12, and near the end ot thelatter the passage 13 forks into two branches 14, so that a solid metalportion 15 is left in the center of the stud 12. Encircling the stud 12is a rubber disk 16, the outer face of which is provided with an annulargroove 17, V-shaped in cross section, which is adapted to tit over therim 18 of the valve of a pneumatic tire.

An important feature of this invention is that the portion of the rubberdisk 16 which contacts with the rim 18 is an annular channel or grooveformedin disk 16,so that both sides of the rim 18 are brought intointimate contact with both walls of the groove 17 so that a perfectairtight union is effected between the rubber disk 16 andthe valve rimwith the valve in order to secure a perfect airtight t. This featureof'the invention is of considerable importance and value because unlessa perfect airtight lit. is produced between the valve and the pressureVan internally shouldered ferrule .19 which is screwed to the lower endofthe inner tube 3'.

As the gage is applied to the valve the stud 12 presses against the endofthe valve stem 2O and depresses the latter, opening the valve 21 topermit air to pass outward through the valve, through the branchpassages 14 and central passage 13 into the interior of the gage. Thesolid metal portion 15 of the stud 12 contacts with the valve 'stem 20so that the two branch air passages 14 are unobstructed and permit thefree passage of air therethrough, and it is preferred to have the stud12 project slightly beyond the face of the rubber disk 16 so that itwill b e sure to depress'the valve stem 2O suffi# ciently to open thevalve, even in cases where the stern 20 is somewhat shorter. However,ordinarily in valves of this't-ype the stem 2() protrudes slightly abovethe rim 18 when the valve is closed.

`When the gage is applied to the valve in the manner indicated, thevalve 21 having been opened by the stud 12, as stated, the air from thevalve passes into the gage and forces out the outer tube 1, \thuselongating .the air chamber within the gage, the outer tube 1 beingextended until the increased tension of the spring 6 eXertsa retainingpower on the outer tube 1 which is equal to the pressure of the air, andat this point outward movement of he outer tube 1 is arrested and theamount of pressure may be read from the graduations 22 which areprovided on the inner tube 3, thel highest graduation revealed by thelower rim of the outer-tube l representing the pressure. ln order topositively limit the outward movement of the tube 1, and also to preventrevoluble movement thereof with respect to the inner tube, aklongitudinal groove 23 is formed in the innr tube 3, the upper end ofthe groove terminating at a shoulder 24, and a projection 25 extendsfrom the outer tube 1 linto the groove 23 and slides in the groove asthe outer tube 1 slides. T he shoulder 24 acts as a stop against whichthe projection 25 strikes to prevent further out- Ward movement of thetube. graduations 22 may be arranged in three rows on the \inner tube 3so as to be easily read after the gage has been applied to the tirevalve without the necessity of turning If desired the e,

the gage around to bring a'row ofgradua- Y f tubes near their oppositeends, a cupped' leather on the inner end of the inner tube bearingagainst the outer tube, a shoulderedplug screwed to the end of the innertube and retaining the cupped leather, air inlet means at the other endof the inner tube, and means for indicating the extension of the outertube.

2. Apressure gage comprising an inner tube, an outer tube slidablethereon, a spring within the tubes connected to opposite ends of thetubes, packing means at the inner end of the inner tube preventingleakage, a plug screwed in the lower end of the inner tube, said plughaving a central stud and `formed with an airpassage with two branchesin the stud leaving a central solid portion on the stud adaptedtocontact with the valve stem of the tire, a rubber disk encircling saidstudjand having an annular groove and means for indicating the extensionof the outer tube, a shouldered `ferru-le screwed on the end of theinnertube `and retaining the rubber disk.

3. A pressure gage comprising an inner tube, an outer tube slidablethereon, a spring within the tubes connected to the respective tubesnear their outer ends, a cupped leather on the inner end of the innertube bearing against the outer tube, a shouldered plug screwed to saidend of the inner tube and retaining the cupped leather, air inlet meansat the outer end of the inner tube, and means for indicating theextension of the outer tube, said plug extending above the cuppedleather, and a pin in the tube to which the spring is, attached, saidplug adapted to strike against said pin.

lin testimony whereof, we have hereunto s'et our hands at Los Angeles,California, this 19th day of August, 1909.

HOWARD BUTTRESS. GEORGE BUTTRESS.

lln presence of- G. T. HACKLEY, FRANK L. A. GRAHAM.

